The one in the middle is directly on top of him. The other two flank it and are meant to catch him if he decides to shift his position to dodge the middle one. If he wants to dodge the three attacks then he will have to shift his position entirely and get out of the way of the Celestials.
But he doesn't plan to do that. He didn't shift during the time the Celestials were approaching him and he won't shift now that they are right on top of him. So he must pay the price for his arrogance.
The three phantom blades came close enough to strike him. He didn't dodge so the one in the middle was about to make contact with him. It chopped down aiming to split him in half. He finally paid attention at the last moment. One of his arms swung a claymore against the middle blade.
The two physically different blades struck each other. One fell from the sky while the other struck from below. Aeternus's defense was a halfhearted swing with minimal power behind the strike. It was as if he was swatting at a fly. And yet the middle blade shattered. It shattered easily into fragments.
The phantom blade shattered because it was weak. It looked whole but it wasn't whole. It had been severely compromised from the inside out. Something ate through it from within. It has become nothing more than a large fragile blade. He knew this so he didn't consider it a threat.
The other two phantom blades swung down past him harmlessly. The Celestial of metal would have frowned if it had a face to frown with. It would also have growled in frustration. Instead, its metal parts vibrated and quivered in agitation. A screech of metal grinding on metal rang out from him. It is a screech of frustration.
It told the others, "Careful. That Demon King is weird. It wields an energy with corrosive properties."
It shouldn't have bothered to. The Celestials found out how corrosive his energy could be immediately. The flurry of attacks that Aeternus sent forward had clashed with their own attacks earlier. He managed to create a small hole in their attacks but that wasn't the end of it. The black arcs of energy tore through their attacks and continued to spread outwards. Each clash between their attacks and his didn't end there. Defeat and victory were not decided immediately.
The black arcs of energy from Aeternus's claymore always rendered the attacks they collided with useless even if they were outmatched in power. Anything that touches them will be made useless after being eaten away. It is as if they are fighting against something acidic with metal.
In the case that the arcs of energy won the initial clash, they will then explode into a small cloud of black energy and spread themselves into the surrounding attacks. The dispersed blackish energy will then erode the surrounding attacks. It unnerved the Celestials.
"It doesn't matter. There's more of us than him." The Celestial of Nature said.
Her words are not mere encouragement. It is the truth. They outnumber Aeternus 10 to 1. They can output far more attacks despite the fact that he has four weapons and four arms. They don't have arms and they don't need them to attack. They attack with their minds and each one of them can produce 10 attacks at a time. There are also 10 of them. He is outnumbered in every way possible. Their attacks continued to advance on Aeternus even though his attacks could take out at least two of theirs on average.
The snake demon and the succubus took in a deep breath when they saw all the attacks approaching Aeternus. They wanted to stop or at least pause and reevaluate their situation. The combined might of the Celestials is that intimidating. The volume of their attack can literally drown them if it is water and if they are mortal. But they didn't stop because Aeternus didn't stop. He continued to approach the Celestials which is according to the plan. So they tried to keep up.
Aeternus continued his futile resistance. He continued to create arcs of energy against the onslaught of attacks. The arcs of energy had a lot of success. They managed to carve out a path for him within the avalanche of attacks. He managed to move closer to the Celestials little by little despite the resistance.
In a fight with weaker beings, what he has achieved is good enough. Unfortunately for him, these are Celestials and they are also elementals. They have perfect control of their attacks. So even though he succeeded in creating a tunnel within the avalanche of attacks, the tunnel collapsed behind him as the Celestials controlled their attacks to move and occupy the vacant space.
He became surrounded immediately. All of his effort was negated. They shut off his forward path and they also shut off his retreat by making some attacks to flank him. Then they attacked him from every direction. He can manage to create a break in the attacks when attacked from the front, but can he do so when attacked from behind, left, right, up, and down?
At the rate of things, he will be drowned before he gets within effective range of the Celestials. The Celestials saw all these happen but they became more vigilant instead of becoming happy. Their attacks will not succeed unless Aeternus is stupid. He is a demon king and no demon king is stupid. They can be rash but not stupid. So Aeternus can't just rush headfirst into their attacks and die. He has to have something up his sleeve and they have to be ready for it.
"Stay alert. Keep our ranks close." The Celestial of Metal warned his fellow Celestials. "Prepare yourself for a desperate Move. Demons are known to be sneaky and scheming."
Aeternus is not stupid and he is not blind despite him not having any eyes. He can see well enough and he can process what he sees to come to the conclusion that he should be in a sorry state if things continue the way they are.
Common sense dictates that he should take a step back immediately and regroup with the other demon kings. Doing so will invalidate his efforts but he will survive after paying a price for his arrogance. But he paid no heed to common sense because he doesn't need common sense.